Deoxygenating apparatus for removing oxygen from water for use in manufacturing beverages are known in the art and generally consist of two types, a deoxygenating column and a deoxygenating tank. A deoxygenating column has a series of stacked deoxygenating units each having a perforated distributor plate and subjacent shallow perforated tray that cooperatively act to create droplets or streams of oxygen-containing water and to direct a stripping gas through the droplets or streams to provide intimate contact between the water and the stripping gas to strip the oxygen from the oxygen-containing water. A layer of water, preferably of uniform depth, forms on the perforated tray with water passing through the perforations forming the droplets or streams. A deoxygenating tank has a tank of oxygen-containing water through which a stripping gas is bubbled to permit the stripping gas to strip the oxygen therefrom. The present invention is more closely related to deoxygenating columns.
U.S. Pat. Nos. 4,358,296 to Notardonato, et al. and 4,265,167 to Mojonnier et al. illustrate deoxygenating columns. Both patents disclose a deoxygenating column having a plurality of stacked deoxygenating units disposed therein. The deoxygenating units consist of a perforated distributor plate defining a central opening therein connected to the inner periphery of the column. A shallow perforated tray is connected to the underside of the plate. The inner periphery of the column and the edge of the tray define an annular passageway. Oxygen-containing water introduced at the top of the column is distributed by the perforated distributor plate onto the tray. The oxygen-containing water is formed into droplets or streams as it passes from the distributor to the tray. A plurality of deoxygenating units are stacked to provide a number of vertical layers of droplets or streams of oxygen-containing water. A stripping gas introduced at the bottom of the column is at best caused to flow only in a vertical serpentine path between the distributor plates and perforated trays as it passes through the column. The stripping gas passes up through the annular passageway, across through the water and up through the central opening.
The deoxygenating columns described above have several problems. First, the structure of the deoxygenating units makes it difficult and expensive to build the column because the distributor plates must be fastened to the inner periphery of the column in a precisely horizontal alignment for the column to function properly.
In addition, after the stripping gas is caused to flow up the central opening it diffuses in all directions toward the annular passageway. Similarly, after the stripping gas flows up the annular passageway it flows in a diffuse stream towards the next central opening. As a result, a particular molecule of stripping gas passes through the streams or droplets of water for only a short distance equal to the length between the edge of the central opening and the annular passageway each time it moves between a distributor and tray. Thus, there is a very limited opportunity for each molecule of stripping gas to intimately contact the oxygen-containing water.
Also, such columns do not ensure that all the stripping gas will flow through the droplets or streams of oxygen-containing water. That is, if one of the distributor plates or trays is not horizontal the layer of oxygen-containing water may not form over an area of the plate or tray meaning no droplets or streams will flow underneath that area. Thus, the portion of the diffuse stream of stripping gas flowing underneath that area will fail to intimately contact any oxygen-containing water. Also, stripping gas can flow through the plate or tray at the area lacking a water layer and thereby bypass the droplets or streams of water.
Moreover, the above-described deoxygenating columns have only a vertical serpentine flow path with limited flow in a horizontal direction. However, only when the stripping is flowing horizontally does it intimately contact the oxygen-containing water. Thus, such deoxygenating columns fail to maximize the opportunity for the stripping gas to intimately contact the oxygen-containing water.
Finally, the above described deoxygenating columns introduce the stripping gas only at the bottom of the column meaning that by the time the stripping gas reaches the top of the column it contains a large amount of the stripped oxygen, decreasing the efficiency of the oxygen exchange process.
The present invention is directed toward overcoming one or more of the problems discussed above.